But some eczema triggers are not so obvious. While reasons for inflammation, itch, and pain will vary from person to person, watch out for the following potential offenders.

1. Candles and Air Fresheners

Fragrances and perfumes in cosmetics and personal-care products are notorious for causing skin reactions, notes the National Eczema Association. But fragrances may lurk in unexpected places, such as in candles and air fresheners. “If a product has a scent, there could be some kind of triggering chemical in there,” says Danilo Del Campo, MD, a dermatologist with the Chicago Skin Clinic. “Candles may especially be an eczema trigger during the winter holidays. People want that holiday feel in the house, but it can cause eczema problems.”

2. Viral Illness

On a blog for the National Eczema Association, Anna Fishbein, MD, an associate professor of pediatrics at Northwestern University’s Feinberg School of Medicine in Chicago, highlighted viral illness as a common and often overlooked eczema trigger. A viral infection like the common cold or flu can stoke systemic inflammation throughout the body, including on the skin. On top of that, the National Eczema Society notes that constant nose blowing due to cold or flu might cause a skin reaction on or around the nose. The Allergy & Asthma Network adds that the herpesvirus, which can cause cold sores in and around the mouth, can lead to atopic dermatitis flares. Herpesvirus also poses a risk of complications including a potentially very serious condition called eczema herpeticum in which infection spreads over wide areas of skin and can even harm organs.

3. Insects

Insect bites can cause trauma to the skin that provokes an eczema flare. When bitten by a bug, the body sends inflammatory chemicals, such as histamine, to the affected area, which in turn might lead to an eczema flare. Cockroaches don’t bite people, but proximity to them can lead to an eczema flare, according to Edidiong Kaminska, MD, a founder and the medical director of Kaminska Dermatology in Chicago. “It’s not the cockroach itself that produces a reaction, but insects carry a lot of things on them,” says Dr. Kaminska. “The particles it sheds can trigger an eczema reaction in the skin.” Some bugs that fuel flares can’t be seen by the naked eye. Dust mites are microscopic, insect-like pests that feed on dead skin and live in bedding, mattresses, upholstered furniture, carpets, or curtains. Some people with atopic dermatitis have an allergic skin reaction to dust mite droppings. Individuals who are sensitive to mites can better protect themselves by regularly cleaning bedding, carpets, and other fabrics.

4. Overwashing

“It’s very common for Americans to take a bath or shower once or even twice a day,” Dr. Del Campo says. “But by overwashing, we lose the natural oils of our skin. The skin then becomes more dry and more prone to developing eczema.” Although thorough hand-washing can destroy bacteria that cause illnesses, too much can further break down the integrity of the skin barrier (which is already compromised in eczema) and lead to flares. The Allergy & Asthma Network advises people to wash with gentle cleansers, use lukewarm water, and moisturize immediately afterward.

5. Jewelry

Not all jewelry aggravates eczema-prone skin, but rings, earrings, necklaces, and other body ornaments made of nickel can be problematic, especially if you have an allergy. According to the Mayo Clinic, a nickel allergy is a common cause of contact eczema, a condition linked to atopic dermatitis. It may not be readily apparent that nickel is in a piece of jewelry, since a small amount of nickel is often mixed into silver or white gold. Individuals can develop an allergy to nickel through repeated and prolonged exposure, and once the allergy is established, the individual will always be sensitive to nickel and will need to avoid contact. Note that eyeglasses, snaps, buttons, and zippers may also contain nickel.

6. Acidic Food

Although not common, food can cause eczema to flare, according to Del Campo. He adds that acidic foods can be a particular issue, including strawberries, tomatoes, and citrus fruits such as oranges, lemons, limes, and grapefruit. For some individuals, other foods can lead to flares as well, including artificial sugars, trans fats, processed meat, red meat, refined carbs, and dairy.

7. Face Masks

Fabrics that trap heat or irritate the skin are well-established troublemakers when it comes to eczema. Polyester, latex, wool, denim, rough linen, and leather can all worsen atopic dermatitis and other forms of skin inflammation, while fabrics made with pure cotton, silk, or bamboo tend to be more eczema-friendly, according to the National Eczema Society. Del Campo suggests that the pandemic introduced a new skin agitator: the face mask. “During the pandemic, we have been seeing a lot of flare-ups around the mouth and on the lips in patients who otherwise were doing well for a long time,” says Del Campo. “People were constantly reusing the same mask, and dyes used in the masks sometimes created a problem. Masking was definitely a new factor that we weren’t expecting.” The Allergy & Asthma Network offers a number of tips on how to reduce the likelihood that a face mask will cause an eczema flare: Cleanse the face with a gentle wash, pat skin dry, and apply moisturizer before putting on a face mask; make sure the mask isn’t too tight (it shouldn’t dig into skin) or too loose (it shouldn’t move around and rub); apply moisturizer again after taking off the mask; and wash a cloth face mask often to remove sweat, oils, skin cells, and germs.